Respuesta :
1) Reactions which involves both a reduction process and a complementary oxidation process are called oxidation-reduction.they can't be double replacement reactions.
Hence,
WO3 + 3H2 ---> W + 3H2O is an oxidation-reduction reaction
Hence,
WO3 + 3H2 ---> W + 3H2O is an oxidation-reduction reaction
Answer: 1. Option A and 2. Option D
In Redox reaction (oxidation-reduction) there should be change in oxidation no.
In A, oxidation no of W is changed from -6 to zero , Reduction (oxidation no Decreased) and oxidation no of Hydrogen is increased from zero to +1, oxidation (increase in oxidation no).
In remaining, there is no change in oxidation number.
2. Greater the concentration, more the collisions between the molecules and more the kinetic energy which reduce the activation energy and speed up the reaction.